Giardia is an infection of the small intestine caused by a protozoa, Giardia lamblia.

Giardia outbreaks can occur in communities in both developed and developing countries where water supplies become contaminated with raw sewage. It can be contracted by drinking water from lakes or streams, where water-dwelling animals such as beavers and muskrats, or domestic animals such as sheep, have caused contamination. It is also spread by direct person-to-person contact, which has caused outbreaks in institutions such as daycare centers.

Travelers are at risk for giardiasis throughout the world. Campers and hikers are at risk if they drink untreated water from streams and lakes. Other risk factors include unprotected anal sex, exposure to a family member with giardiasis, and institutional (daycare or nursing home) exposure.

• Diarrhea
• Abdominal pain
• Gas or bloating
• Abdomen swollen or distended
• Nausea
• Loss of appetite
• Vomiting
• Headache
• Low grade fever

The time between being infected and developing symptoms is 7 - 14 days. The acute phase lasts 2 - 4 weeks.

Tests that may be done include:

• EIA test to check for Giardia
• Small bowel biopsy
• Stool ova and parasites exam
• String test (rarely performed)

This disease may also alter the results of the following tests:

• D-xylose absorption
• Small bowel tissue biopsy smear
• Smear of duodenal aspirated fluid